Hole-opener tool

ABSTRACT

A hole-opener tool for use in enlarging a well-bore. It includes a body arranged for attachment at the upper end to a rotary drill string or the like, and having a lower end arranged for positioning in the well-bore to be enlarged. The body has a plurality of vertically extending slots which are generally dovetailed in transverse section. Each of the slots is arranged to receive a removable cutter arm adapted for insertion in and retention therein. Each of the arms has a dove-tail shaped retaining portion which mateably engages the dove-tail slots, whereby the arms are held against radial and circumferential displacement relative to the body. The arms are also held in position by retainer pins passing through the body and engaging the arm, and cutter rollers are supported on the arms for cutting the wall of the adjacent well-bore to enlarge the same.

' United States Patent 1191 Hester 1 Nov. 4, 1975 HOLE-OPENER TOOL 733,596 7/1955 United Kingdom 175/406 [76] Inventor: John W. Hester, 242 Idlewild Drive, I

Houma 70360 Primary Examiner-David H. Brown [22] Filed: July 22, 1974 [21] Appl. No.: 490,256

[57] ABSTRACT [52] U.S. Cl. 175/339 175/344; 175/353 511 1m. (:1. E21B 9/10; E21B 9/24 A hole-Opener for use in enlarging a Well-bore It 58 Field of Search 175/344-3411, includes a body arranged for attachment at the upper 175 334 335 353 40 412 413, 382, 339 end to a rotary drill string or the like, and having a lower end arranged for positioning in the well-bore to 5 References Cited be enlarged. The body has a plurality of vertically ex- UNITED STATES PATENTS tending slots which are generally dove-talled in transverse section. Each of the slots is arranged to receive 1,375,094 4/1921 Humason 175/342 X a removable cutter arm adapted for insertion in and ag h g g retention therein. Each of the arms has a dove-tail 208675l 7/1937 Taylgor 175/347 X shaped retaining portion which mateably engages the 2:103:5s3 12/1937 Howard; aiii :1... 175 344 dove-tail Slots whereby the arms are held against 2,139,030 2/1940 Harrington 175/346 dial and circumferential displacement relative to the 2,189,035 2/1940 Squires 175/346 body. The arms are also held in position by retainer 2,260,366 10/1941 Childs..... 175/346 pins passing through the body and engaging the arm, 38 ll/l954 obe ts 175/406 X and cutter rollers are supported on the arms for cut- 3303900 2/1967 Kloescl at al 175/)6 X ting the wall of the adjacent well-bore to enlarge the 3,306,381 2/1967 Garrett et al. 175/346 Same.

FOREIGN PATENTS OR APPLICATIONS 1,257,200 2/1961 France 175/334 4 Claims, 3 Drawing Figures F '1 2 1 2 6- 1 I 25 27 I 2 1 -28 HOLE-OPENER TOOL I BACKGROUND OF THE INVENTION a. Field of the Invention This invention relates to a hole-opener tool foruse in enlarging a well-bore or the like. More particularly, it relates to an improved hole-opener tool wherein the cutting means are supported on mechanically removable and replaceable arms and wherein different arms of larger or smaller configuration can be used with the body of the tool for making either larger or smaller hole openings in the well-bore. In addition, the invention permits the use of different size bodies with the same cutter assemblies.

b. Description of the Prior Art Previous hole-opener tools which have been available to the art include tools having the cutter arms which are permanently attached or made a part of the main body and wherein the cutting rollers themselves are replaceable. Other tools are arranged suchthat the cutting assemblies are welded to the main 'body, which is both costly and time-consuming to effect removal or replacement of the cutting elements. Moreover, the aforesaid types of hole-opening tools do not provide the flexibility of having one tool which can be used to open various size holes by merely substituting larger or smaller cutter arms for cutter assemblies. Certain other prior art tools are the type which have cutting arms attached to the body and are pivotal outwardly therefrom. However, these tools suffe'r certain disadvantages in that quite often the pivotedarms become bent or broken prematurely and are limited in the extent of thrust forces which may be applied thereto.

SUMMARY OF THE INVENTION It is therefore an object of this invention to provide an improved hole-opening tool wherein the cutters can be changed mechanically when'worn and wherein the cutter arms are mechanically interchangeable with smaller and larger arms and wherein various size bodies may accommodate a plurality of arms of the same size. These and other objectives of the invention will be apparent from the description which follows.

Briefly stated, this invention is for a hole-opener tool for use in enlarging a well-bore or the like. It includes, in combination, a body arranged for attachment at the upper end thereof to a rotary drill string. The body'has a lower end which is dimensioned for positioning in the well-bore to be enlarged. Further, the body ha's a plurality of vertically extending slots spaced circumferentially thereabout with the slots'each being dove-tailed in transverse section. The invention includes removable cutter arms adapted for insertion into and retention in each of the slots, with the arms each having a dove-tailed retaining portion on the radially inward side thereof, mateably engageable in one of the slots for holding the arms against circumferential and radial dis placement relative to the body. Means are carried by the body for retaining and holding the arms against longitudinal displacement relative to the body. Each of the arms carries cutting means, such as rolling cones or the like, for cutting away adjacent portions of the wall of the well-bore upon rotation of the body to thereby enlarge the well-bore. The invention provides cutting means which may be replaced by removal of the arms. In certain embodiments of the invention, the slots are preferably closed at the upper end thereof and opened at the lower end thereof. Further, each of the cuter arms is arranged for insertion of the retaining portion through said open end of a slot and for abuttment againstthe closed upper end of the slot in which each is mounted, thus providing a tool which can withstand greater compression or thrust forces thereon.

DESCRIPTION or THE DRAWING FIG. 1 is a generally 'side elevation view ofone pres ently preferred embodiment of a tool of this invention,

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, the tool of this invention generally includes a body designated by the numeral 11 as provided with a threaded upper end 12 which is arranged 'for attachment of inclusion in a rotary drill string, for example. In addition, body 11 is provided with a threaded lower end 13 to which is threaded a ball-nose sub 14. It will be noted that lower end 13 and sub 14 are dimensions for insertion into the bore which is being enlarged. Further, it should be understood that lower end 13 could be attached to other subs or additional pipe or even a drill bit for drilling the initial well-bore. I

Body 11 is provided an enlarged portion l5 having a plurality of circumferentially spaced and generally longitudinally extending or vertically extending slots 17 which are generally dove-tailed in transverse section, as

best seen in FIG..2. Further, and preferably, each of the slots 17 is closed at the upper end thereof and preferably is tapered radially inwardly and upwardly as shown in FIG. 1 so as to provide a tapered shoulder 18. Further, each of the slots 17 is open at the lower end thereof, as shown in FIG. I, for purposes of receiving a cutting assembly which will not be described.

The tool includes a plurality of removable cutter arms 20, each of which is adapted for insertion into and retention in one of the slots 17. Each of the arms 20 have a radially inward dove-tailed retaining portion 21 on the radially inward side thereof, which is arranged for mateable engagement in one of the slots 17 and for holding the arms 20 against circumferential and radial displacement relative to body 11. Each of the cutter arms 20 has a slanted top-end 44 which is arranged for mating abuttment against a shoulder 18. Hence, downward thrust on body 11 when cutter arms 20 are in the cutting position will cause cutter arms 20 to be forced radially inwardly, thereby providing greater strength to the tool.

Each of the cutter arms 20 has a depending shank 26 which supports the outward end of a cutter pin 27 on which is mounted a rolling cutter in the form of a cutte cone 28, which are of conventionaljdesignl Cutter arms 20 are arranged for mounting on body 11 by being passed upwardly through the open lower end ofa slot 17, such that the top end 24 engages shoulf der l8 and are held there by a pair of threaded retainer pins 29' which are arranged for generally transverse passage through appropriate pin holes provided in body 11 and for engagement with the half-circle recesses 31' on the back side of cutter arms as shown.

It will also be understood that body 11 of the invention has a bore 39 therethrough whereby drilling fluid may be passed downwardly therethrough. Further, body 11 may have appropriate conduits therethrough for mating with conduits through cutter arms 20 so as to provide a flow of drilling mud past cutting cones 28. By way of example, body 11 may be provided with openings 34 which mate with channels 35 in each of the cutter arms 20, which channels discharge on the up ward side of each of the cutting cones 28.

In operation, the tool of this invention is assembled in the condition generally shown in FIG. I. Thereafter, tool body 11 can be incorporated in an appropriate drill string of conventional designand the tool lowered in a well-bore to carry out the hole-opening operation. Upon rotation of the drill string, body-l1 and cutter arms 20 are rotated therebyeffecting rotation of cutting cones 28 to effect cutting of the wall of the adjacent well-bore, to thereby enlarge the same. At such time that the cutting cones 28 become dull or need to be replaced, then the tool can be removed from the well-bore and new cutting arms 20 substituted by removal of pins 29 and substitution of a new cutter arm 20 and replacement of the aforesaid pins 29; In the event it is desired to use body 11 to effect the drilling of either a larger or smaller diameter hole, then cutter arms of a different size can be inserted into too] body 11 as described above, thereby making the tool adaptable or useful over a large range of hole sizes. Alternatively, cutter arms 20 can be of the uniform size and shape and used in combination with tool bodies of different diameters. l

It will thus be apparent that this arrangement of a tool permits the use of one tool body for different hole diameters by changing the cutter arm. In addition, the

aforesaid cutter arms can be used with different sized v bodies to permit greater diameter flexibility with less number of tools required in stock. The arrangement of the toolmakes the replacement of the cutter arms and cutting elements much more convenient and yet provides a tool which is of sufficient strength to withstand great forces and long-time operations. I

Further modifications andalternative embodiments of the apparatus and method of this invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be con-.

strued as illustrative only and is for the purpose of teaching-those skilled in the art the manner of carryingdescribed herein,parts may be reversed, and certain features of the invention may be utilized independently of the use of other features, all as would be apparent to one skilled in the art after having the benefit of this description of the invention.

What is claimed is:

1. In a hole opener tool for use in drilling a well-bore to-a larger diameter, the combination comprising:

a body arranged for attachment at the upper end thereof to a rotary drill string and having a lower end dimensioned for positioning in the well-bore to be drilled larger, said body having a plurality of vertically extending slots spaced circumferentially thereabout, said slots each being dove-tailed in transverse section and closed at the upper end thereof and open at the lower end thereof, and said body having bore means therethrough communieating with the'bore of said drill string for conducting drilling fluid therethrough;

a removable cutter arm adapted for insertion into and retention in'each of said slots through said lower open end and abutment against said closed upper end, said arms each having a dove-tailed retaining portion on the radially inward side thereof mateably engageable in one of said slots for holding said arms against circumferential and radial displacement relative to said body, and each of said arms having a bore therethrough communicating with said bore means of said body;

retainer means carried by said body for holding said arms against'longitudinal displacement relative to said body; I

and a rolling cone cutter member carried by each of said arms for cutting away adjacent portions of the wall of said well-bore upon rotation of said body to thereby drill-said well-bore larger, whereby said cutter members may be replaced by removal of said arms, and said'cutter members each being positioned in said arms such that drilling fluid passing through said bore of said arm will impinge thereagainst. 2. The invention as claimed in claim 1 wherein said retainer means'includes: 1 1

a plurality of removable pins, each of which is ,ar-

. ranged for passage through a portion of said body and engaging a portionof one of said arms. 3. The invention as claimed in claim 1 wherein: the upper end of each of said slots is closed by a portion of said body which is tapered upwardly and radially inwardly. 4. The invention as claimed in claim 3 wherein: the upper end of each of said arms is tapered up wardly and radially. inwardly to match the tapered surface of'the upper closed end of said slot in which said arm is received. 

1. In a hole opener tool for use in drilling a well-bore to a larger diameter, the combination comprising: a body arranged for attachment at the upper end thereof to a rotary drill string and having a lower end dimensioned for positioning in the well-bore to be drilled larger, said body having a plurality of vertically extending slots spaced circumferentially thereabout, said slots each being dove-tailed in transverse section and closed at the upper end thereof and open at the lower end thereof, and said body having bore means Therethrough communicating with the bore of said drill string for conducting drilling fluid therethrough; a removable cutter arm adapted for insertion into and retention in each of said slots through said lower open end and abutment against said closed upper end, said arms each having a dovetailed retaining portion on the radially inward side thereof mateably engageable in one of said slots for holding said arms against circumferential and radial displacement relative to said body, and each of said arms having a bore therethrough communicating with said bore means of said body; retainer means carried by said body for holding said arms against longitudinal displacement relative to said body; and a rolling cone cutter member carried by each of said arms for cutting away adjacent portions of the wall of said wellbore upon rotation of said body to thereby drill said well-bore larger, whereby said cutter members may be replaced by removal of said arms, and said cutter members each being positioned in said arms such that drilling fluid passing through said bore of said arm will impinge thereagainst.
 2. The invention as claimed in claim 1 wherein said retainer means includes: a plurality of removable pins, each of which is arranged for passage through a portion of said body and engaging a portion of one of said arms.
 3. The invention as claimed in claim 1 wherein: the upper end of each of said slots is closed by a portion of said body which is tapered upwardly and radially inwardly.
 4. The invention as claimed in claim 3 wherein: the upper end of each of said arms is tapered upwardly and radially inwardly to match the tapered surface of the upper closed end of said slot in which said arm is received. 